In 1982 I started research into the interaction of a seagoing cutter dredge with the soil, resulting in the program Dredmo. From 1983 to 1987 my PhD research resulted in a more fundamental model for the cutting of water saturated sand. The model however already contained terms that made it suitable for other types of soil like clay and rock. First ductile failure modes were investigated and later brittle failure modes were added.
The model distinguishes 6 possible failure mechanisms for small blade angles:
The Flow Type. This is the basic mechanism, all other mechanisms start from the Flow Type. The Flow Type describes ductile shear failure in clay and rock.
The Shear Type. The Shear Type is mathematically equivalent to the Flow Type, but is applied to sand cutting.
The Crushed Type. The Crushed Type is mathematically equivalent to the Flow Type, but is applied to atmospheric and hyperbaric rock cutting.
The Curling Type. The Curling Type occurs in clay cutting and hyperbaric rock cutting when cutting a very thin layer of material.
The Tear Type. The Tear Type describes tensile failure in clay cutting, so brittle tensile failure.
The Chip Type. The Chip Type desribes tensile/shear failure in rock cutting, so brittle tensile or shear failure.
For large blade angles the wedge theory has been developed. A static or dynamic wedge will occur in front of the blade, reducing the cutting forces.
The model is now a generic model for cutting of sand, clay and rock and also hyperbaric rock and is published in October 2014 in a book named: The Delft Sand, Clay & Rock Cutting Model. Published by IOS Press. www.iospress.nl.
The developments of the model and the book will be updated on this website.
For questions, remarks and requests contact Dr.ir. S.A. Miedema, email: firstname.lastname@example.org